java.lang.Object
- org.mitre.synthea.world.concepts.PediatricGrowthTrajectory

All Implemented Interfaces:

java.io.Serializable
```
public class PediatricGrowthTrajectory
extends java.lang.Object
implements java.io.Serializable
```
This class provides growth trajectories for individuals between 2 and 20. For a person, starting at age 2, the trajectory will set an age + 1 year BMI. The BMI will be selected by computing the person's current extended BMI Z score. The + 1 year extended BMI Z score will be selected from a normal distribution with a mean that is based on the previous score, correlation between extended BMI Z scores from year to year and difference in mean extended BMI Z scores from year to year.
This method uses extended BMI Z Scores, which is a concept under development at CDC. The current growth charts, were not intended to be used beyond the 97th percentile. See: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4528342/

Further, CDC growth chart data is from 1960-1990. CDC defines obesity in children as having a BMI at or above the 95th percentile for sex and age in months: https://www.cdc.gov/obesity/childhood/defining.html However, recent data shows that at least 18.5% of children have obesity: https://www.cdc.gov/obesity/data/childhood.html This oddly means that more than 18.5% of the population have a BMI greater than the 95th percentile.

To account for these issues, this class uses correlations and means gathered from more recent NHANES data: https://wwwn.cdc.gov/nchs/nhanes/Default.aspx

The class also uses extended BMI Z scores. For children with a BMI value less than the 95th percentile, regular Z scores are used. At or above the 95th percentile models BMI values as a half normal distribution with a parameter sigma that is age based. The value for sigma is calculated using a quadratic function with weights obtained by examining NHANES data ADD CITATION ONCE PUBLISHED BY CDC

See Also:

Serialized Form

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`class`	`PediatricGrowthTrajectory.Point`	A representation of a point in the growth trajectory.
`static class`	`PediatricGrowthTrajectory.YearInformation`	Container for data on changes between years for BMI information.

Field Summary

Fields
Modifier and Type	Field	Description
`static int`	`NINETEEN_YEARS_IN_MONTHS`
`static long`	`ONE_YEAR`
`static double`	`SIGMA_FEMALE_A`
`static double`	`SIGMA_FEMALE_B`
`static double`	`SIGMA_FEMALE_C`
`static double`	`SIGMA_MALE_A`
`static double`	`SIGMA_MALE_B`
`static double`	`SIGMA_MALE_C`

Constructor Summary

Constructors
Constructor Description

PediatricGrowthTrajectory(long personSeed, long birthTime)
Starts a new pediatric growth trajectory.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`addPoint(int ageInMonths, long timeInSimulation, double bmi)`	Adds a point to the end of the trajectory.
`void`	`addPointFromPercentile(int ageInMonths, long timeInSimulation, double percentile, java.lang.String sex)`	Adds a point to the end of the trajectory.
`boolean`	`beforeInitialSample(long time)`	Determines whether the given time is before or after the NHANES sample selected as the seed for this growth trajectory.
`double`	`currentBMI(Person person, long time)`	Provides the BMI for the individual at the supplied time.
`static double`	`extendedZScore(double bmi, int ageInMonths, java.lang.String sex, double sigma)`	Calculates the extended BMI Z Score.
`void`	`generateNextYearBMI(Person person, long time)`	Generates a BMI for the person one year later.
`PediatricGrowthTrajectory.Point`	`justAfter(long time)`	Finds the closest point occurring after the given time.
`PediatricGrowthTrajectory.Point`	`justBefore(long time)`	Finds the closest point occurring before the given time.
`static java.util.Map<java.lang.String,PediatricGrowthTrajectory.YearInformation>`	`loadCorrelations()`	Load correlations of extended BMI Z Scores from age year to age year.
`static double`	`percentileToBMI(double percentile, int ageInMonths, java.lang.String sex, double sigma)`	Uses extended percentiles when calculating a BMI greater than or equal to the 95th percentile.
`double`	`reverseWeightPercentile(java.lang.String sex, double heightPercentile)`	Given the sex, BMI and height percentile at age 2, calculate the correct weight percentile.
`static double`	`sigma(java.lang.String sex, double age)`	Calculate the parameter needed to model the half normal distribution for BMI values at or above the 95th percentile.
`PediatricGrowthTrajectory.Point`	`tail()`	Finds the last point of the growth trajectory.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - SIGMA_FEMALE_A
```
public static double SIGMA_FEMALE_A
```
  - SIGMA_FEMALE_B
```
public static double SIGMA_FEMALE_B
```
  - SIGMA_FEMALE_C
```
public static double SIGMA_FEMALE_C
```
  - SIGMA_MALE_A
```
public static double SIGMA_MALE_A
```
  - SIGMA_MALE_B
```
public static double SIGMA_MALE_B
```
  - SIGMA_MALE_C
```
public static double SIGMA_MALE_C
```
  - ONE_YEAR
```
public static long ONE_YEAR
```
  - NINETEEN_YEARS_IN_MONTHS
```
public static int NINETEEN_YEARS_IN_MONTHS
```
- Constructor Detail
  - PediatricGrowthTrajectory
```
public PediatricGrowthTrajectory(long personSeed,
                                 long birthTime)
```
    Starts a new pediatric growth trajectory. Selects a start BMI between 2 and 3 years old by pulling a weighted sample from NHANES.
    
    Parameters:
    
    personSeed - The person's seed to allow for repeatable randomization
    
    birthTime - The time the individual was born in the simulation
- Method Detail
  - reverseWeightPercentile
```
public double reverseWeightPercentile(java.lang.String sex,
                                      double heightPercentile)
```
    Given the sex, BMI and height percentile at age 2, calculate the correct weight percentile.
    
    Parameters:
    
    sex - of the person to get the weight percentile for
    
    heightPercentile - or the person
    
    Returns:
    
    the weight percentile the person would have to be in, given their height percentile and BMI
  - generateNextYearBMI
```
public void generateNextYearBMI(Person person,
                                long time)
```
    Generates a BMI for the person one year later. BMIs are generated based on correlations measured between years of age and differences in mean BMI. This takes into special consideration people at or above the 95th percentile, as the growth charts start to break down.
    
    Parameters:
    
    person - to generate the new BMI for
    
    time - current time
  - tail
```
public PediatricGrowthTrajectory.Point tail()
```
    Finds the last point of the growth trajectory.
    
    Returns:
    
    the point
  - justBefore
```
public PediatricGrowthTrajectory.Point justBefore(long time)
```
    Finds the closest point occurring before the given time.
    
    Parameters:
    
    time - time of interest
    
    Returns:
    
    Point just before it or null if it doesn't exist
  - justAfter
```
public PediatricGrowthTrajectory.Point justAfter(long time)
```
    Finds the closest point occurring after the given time.
    
    Parameters:
    
    time - time of interest
    
    Returns:
    
    Point just after it or null if it doesn't exist
  - beforeInitialSample
```
public boolean beforeInitialSample(long time)
```
    Determines whether the given time is before or after the NHANES sample selected as the seed for this growth trajectory.
    
    Parameters:
    
    time - The time to check
    
    Returns:
    
    true if the time is before the sample
  - addPoint
```
public void addPoint(int ageInMonths,
                     long timeInSimulation,
                     double bmi)
```
    Adds a point to the end of the trajectory. It must be at the end of the trajectory, otherwise, it will throw an IllegalArgumentException.
    
    Parameters:
    
    ageInMonths - for the person at the point
    
    timeInSimulation - at the time of the point
    
    bmi - what the body mass index should be at that point in time
  - addPointFromPercentile
```
public void addPointFromPercentile(int ageInMonths,
                                   long timeInSimulation,
                                   double percentile,
                                   java.lang.String sex)
```
    Adds a point to the end of the trajectory. It must be at the end of the trajectory, otherwise, it will throw an IllegalArgumentException.
    Instead of providing a BMI, provide a percentile, which will get converted to a BMI
    
    Parameters:
    
    ageInMonths - for the person at the point
    
    timeInSimulation - at the time of the point
    
    percentile - the percentile
    
    sex - the sex of the individual
  - currentBMI
```
public double currentBMI(Person person,
                         long time)
```
    Provides the BMI for the individual at the supplied time. If the time provided is beyond the current length of the trajectory, it will generate a new point in the trajectory, if that point will happen before the person is 20 years old.
    
    Parameters:
    
    person - to get the BMI for
    
    time - the time at which you want the BMI
    
    Returns:
    
    a BMI value
  - percentileToBMI
```
public static double percentileToBMI(double percentile,
                                     int ageInMonths,
                                     java.lang.String sex,
                                     double sigma)
```
    Uses extended percentiles when calculating a BMI greater than or equal to the 95th percentile.
    
    Parameters:
    
    percentile - BMI percentile {0 - 1}
    
    ageInMonths - of the person
    
    sex - of the person
    
    sigma - age based value to model the extended percentiles
    
    Returns:
    
    The BMI, offering a different value than the growth charts when above the 95th
  - extendedZScore
```
public static double extendedZScore(double bmi,
                                    int ageInMonths,
                                    java.lang.String sex,
                                    double sigma)
```
    Calculates the extended BMI Z Score. This is the regular Z Score when below the 95th percentile. Above that, a different, half normal distribution is used to model the values.
    
    Parameters:
    
    bmi - you want the Z Score for
    
    ageInMonths - of the person
    
    sex - of the person
    
    sigma - age based value to model the extended percentiles
    
    Returns:
    
    the extended Z Score
  - sigma
```
public static double sigma(java.lang.String sex,
                           double age)
```
    Calculate the parameter needed to model the half normal distribution for BMI values at or above the 95th percentile.
    
    Parameters:
    
    sex - of the person
    
    age - of the person, precision matters! You probably don't want to pass an integer like value
    
    Returns:
    
    sigma to use in other calculations
  - loadCorrelations
```
public static java.util.Map<java.lang.String,PediatricGrowthTrajectory.YearInformation> loadCorrelations()
```
    Load correlations of extended BMI Z Scores from age year to age year.
    
    Returns:
    
    The correlations keyed by age year

Class PediatricGrowthTrajectory

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

SIGMA_FEMALE_A

SIGMA_FEMALE_B

SIGMA_FEMALE_C

SIGMA_MALE_A

SIGMA_MALE_B

SIGMA_MALE_C

ONE_YEAR

NINETEEN_YEARS_IN_MONTHS

Constructor Detail

PediatricGrowthTrajectory

Method Detail

reverseWeightPercentile

generateNextYearBMI

tail

justBefore

justAfter

beforeInitialSample

addPoint

addPointFromPercentile

currentBMI

percentileToBMI

extendedZScore

sigma

loadCorrelations